This invention relates in general to metal picket fences and, more specifically, to a method and apparatus for assembling a strong, rigid metal picket fence from pre-formed components.
A wide variety of metal picket fences have been made in the past. Generally, a number of vertical pickets, which may be rods or tubes of metal, are welded to upper and lower cross pieces to form panels. The panels are then fastened to posts, generally by welding where metal posts are used or bolted or screwed fittings where posts of other material are used or where the panel is to be installed over a window or the like. While sturdy, these fences have a number of problems. The welded areas are prone to rusting, even if painted. Where galvanized components are used, welding will destroy the coating at the weld areas, leading to rusting. Since these panels are generally assembled and welded at a factory, panels cannot be varied to accommodate irregular ground surfaces. Welding the panels on site requires complex and heavy jigs and fixtures and welding equipment. Also, considerable skill and time is required to properly assemble the fence panels and fence on site.
Attempts have been made to design fence panels that can be assembled or adjusted on site. These fences and fence construction methods tend to lack sturdiness and ease of assembly. Miller, in U.S. Pat. No. 1,791,680 describes a joint lock for use in the construction of grill-work for fastening bars to rails and rails to posts. Bos describes in U.S. Pat. No. 3,411,752 a guardrail construction that may be delivered to a site in a knocked-down condition an erected there. U.S. Pat. No. 3,707,276, issued to Fraincis et al. describes a variety of aluminum rail extrusions for fence construction, with pickets pivoted to the rails by bolts extending through the pickets and top and bottom rails. Each of these fences construction systems suffers from the problems described above.
Thus, there is a continuing need for improved methods and apparatus for constructing metal picket fences that can be conveniently assembled on site from standard components, that provide a sturdy and long lived fence, that can be assembled from galvanized components without damaging or destroying the galvanized coating.